The Mandela Effect is a recent phenomenon that is believed to be caused by confabulations, or false memories, involving certain events happening at different times that "were believed to be remembered", and different spellings of products "than perceived". The term was coined by Fiona Broome, a paranormal consultant, in 2010 . However, it was most likely not largely widespread until the deaths of Jan Berenstain and Nelson Mandela in 2012 and 2013 respectively. Some believe most older millennials and generations before were born in an "alternate universe" but were shifted into another one within the past several years (thus explaining the minor differences).
Berenstain Bears Edit
Perhaps the most prominent example of the Mandela Effect is the Berenstain Bears, a popular American children's book series and cartoon. Thousands, perhaps even millions, of millennials who once watched the TV series, as well as the younger baby boomers and "Gen X's" who were read the books as children, remember the spelling as "Berenstein" rather than the correct "Berenstain". YouTuber SEFD Science published a video in September 2015 trying to disprove the "alternate universe" theory (that is, in the alternate universe it was spelled "Berenstein") (Video Here). SEFD Science in the video says that "recalling a memory" in reality is actually not recalling it at all, but rather "reconstructing it from nothing or from scratch" . YouTube channel New Rockstars lists examples in TV Guides that do have the spelling as "Berenstein" as well as a book where Panda neighbors move in, which according to the cover shows "Papa Bear" pissed off (possibly proving Papa Bear is a WASP) .
'Stein' is the German word for "stone" and it appears frequently in English, for example in the name of Albert Einstein. People familiar with English words including 'Stein' are likely to remember the name as 'Berenstein' incorrectly.
Snow White Edit
One of the first lines in the movie Snow White and the Seven Dwarfs by the "evil witch" is "Magic mirror on the wall, who is the fairest one of all ?" However, many remember the above-line as "Mirror, mirror on the wall, who is the fairest one of all?" A YouTuber by the name of Become One That Can See somewhat proves that the lines actually are "Mirror, mirror on the wall" by showing book-proof. The book shown is from the 1970s .
Death of Nelson Mandela Edit
Nelson Mandela died on December 5, 2013. However, some people seem to remember him dying while he was still in prison, sometime during the 1980s. Fiona Broome, the one who coined the term "Mandela Effect", wrote in an article how she remembers news reports about his death, his funeral and even riots in nearby-South African cities. One commenter mentioned March 1983 based on his journal writings surrounding the supposed event . However, she later found out Mandela was in fact still alive and shrugged it off, only to find out at a convention many others remember exactly what she did  .
Looney Tunes Edit
To Be Added Later
Possible Explanations Edit
Occam's Razor Edit
Occam's Razor is a philosophical aspect basically stating that the simpler assumption of two (or more) assumptions is more likely to be true. In other words: the more assumptions you make, the less likely it is to be true  ! SEFD Science uses this explanation to help explain his mis-remembrance of the series being spelled "Berenstein".
Spelling/Suffix Popularity Edit
For the Berenstain Bears conspiracy, another explanation made by SEFD Science is the popularity of the suffix "stein". Mike Berenstain, son of the late Stan and Jan Berenstain (creators of the book series), submitted an email with a link to a recalling in an autobiography by Stan Berenstain. This recalling was during Stan's 4th grade year during roll call when the teacher stated "there was no such thing as a 'Berenstain' spelling" .
Book vs. Movie Confusion Edit
For the Snow White Conspiracy, it is entirely possible that post people misremembering the witches line as "Mirror, mirror on the wall" instead of "Magic mirror on the wall" were thinking about the book's quote rather than the movie's. According to mandelaeffect.com, the book is originally German, and the lines "Spieglein, spieglein" translates via Google to "Mirror, Mirror". Alternate Memories or possibly even Occam's Razor could be the cause to this mis-remembrance .
 http://mandelaeffect.com/nelson-mandela-died-in-prison/ (Make sure to read the comment section as well!)